Obviously the "host your own game feature" isn't working actually. I myself have no info, why this is the case.
You will get an error like "forbidden". No worries, that does not mean that you are banned from hosting.
Sillysoft is informed and will hopefully fix this problem soon. In the meantime we can only use sillysofts EUROPE hosts. They seem to work fine.

Update 08/03/2016: Problems seem to be fixed, You should be able to host again ...